<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>front end 3</title>
    <link rel="stylesheet" href="fe3.css">
    <style>
        h1 {
            background: lightblue;
        }

        #id-h1 {
            background: yellow;
        }

        .juran-title {
            background: blue;
        }
    </style>
</head>
<body>
<div>
    <h1 style="color:red;">hello juran</h1>
    <h1 id='id-h1'>E = MC<span class="square">2</span></h1>
    <h1 class="juran-title">hello class</h1>
</div>
</body>
</html>